Equilibrium and Support Reactions

2021 ◽  
pp. 47-62
Author(s):  
Debabrata Podder ◽  
Santanu Chatterjee
Keyword(s):  
Support Reactions

scholarly journals A Vibrissa-Inspired Highly Flexible Tactile Sensor: Scanning 3D Object Surfaces Providing Tactile Images

Sensors ◽  
2021 ◽  
Vol 21 (5) ◽  
pp. 1572
Author(s):  
Lukas Merker ◽  
Joachim Steigenberger ◽  
Rafael Marangoni ◽  
Carsten Behn
Keyword(s):  
Steel Wire ◽  
Sense Organ ◽  
Tactile Sensor ◽  
Tactile Sensors ◽  
Measuring Device ◽  
3D Object ◽  
Torque Transducer ◽  
Sense Of Touch ◽  
Important Basis ◽  
Support Reactions

Just as the sense of touch complements vision in various species, several robots could benefit from advanced tactile sensors, in particular when operating under poor visibility. A prominent tactile sense organ, frequently serving as a natural paragon for developing tactile sensors, is the vibrissae of, e.g., rats. Within this study, we present a vibrissa-inspired sensor concept for 3D object scanning and reconstruction to be exemplarily used in mobile robots. The setup consists of a highly flexible rod attached to a 3D force-torque transducer (measuring device). The scanning process is realized by translationally shifting the base of the rod relative to the object. Consequently, the rod sweeps over the object’s surface, undergoing large bending deflections. Then, the support reactions at the base of the rod are evaluated for contact localization. Presenting a method of theoretically generating these support reactions, we provide an important basis for future parameter studies. During scanning, lateral slip of the rod is not actively prevented, in contrast to literature. In this way, we demonstrate the suitability of the sensor for passively dragging it on a mobile robot. Experimental scanning sweeps using an artificial vibrissa (steel wire) of length 50 mm and a glass sphere as a test object with a diameter of 60 mm verify the theoretical results and serve as a proof of concept.

Long-term performance of prestressed concrete continuous box girders in the natural environment

2020 ◽  
Vol 47 (7) ◽  
pp. 856-864
Author(s):  
Guohui Cao ◽  
Wang Zhang ◽  
Jiaxing Hu ◽  
Xirong Peng
Keyword(s):  
Prestressed Concrete ◽  
Load Test ◽  
Time Dependent ◽  
Material Strength ◽  
Practical Calculation ◽  
Box Girders ◽  
Load Types ◽  
In The Beginning ◽  
Support Reactions

A long-term load test performed for 470 days on two two-span prestressed concrete (PC) continuous box girders is reported in this paper. Load types were selected as the test variates, and structural responses such as support reactions, deflections, and concrete strains were monitored. Simultaneously, affiliated experiments such as material strength, creep, and shrinkage tests were conducted to investigate the time-dependent performances of the materials. Data obtained from these tests showed that deflections, strains, and support reactions develop rapidly in the beginning and stabilize afterward; the reactions of mid- and end-supports decline and rise over time, respectively. Time-dependent patterns of deflections and support reactions were analyzed on the basis of an effective modulus method, and a practical calculation method for long-term deflections considering reaction redistributions was proposed. The effects of the service environment on the performance of PC girders were evaluated through an incremental analysis method.

Highway 400 precast concrete inlay panel project: Instrumentation plan, installation, and preliminary results

2018 ◽  
Vol 45 (10) ◽  
pp. 889-898 ◽  
Author(s):  
Daniel Pickel ◽  
Susan Tighe ◽  
Warren Lee ◽  
Rico Fung
Keyword(s):  
Static Load ◽  
Asphalt Pavement ◽  
Precast Concrete ◽  
Earth Pressure ◽  
Load Testing ◽  
Dry Conditions ◽  
Rehabilitation Strategy ◽  
Support Reactions ◽  
Precipitation Events ◽  
Static Load Testing

The Ministry of Transportation of Ontario was interested in a rehabilitation strategy that could be used to address deep-seated rutting issues encountered on its 400-series highways. A precast concrete inlay panel (PCIP) rehabilitation design was developed and constructed involving the installation of precast panels into partially-milled asphalt pavement. Sub-surface instrumentation was installed at the PCIP–asphalt interface including earth pressure cells and moisture sensors installed in six instrumentation clusters. This instrumentation has been monitored to gather information regarding the PCIP trial installation. Readings from the moisture sensors indicate that water penetrates beneath the PCIPs in precipitation events, though these moisture levels recede under dry conditions, indicating that the water can exit the sub-slab area. Static load testing using a fully-loaded gravel truck was used to determine the different support reactions caused by different loading configurations. Higher loads were generally found beneath the joints in the two loading situations studied.

scholarly journals ANALISIS GAYA GEMPA PADA BANGUNAN RUMAH TINGGAL DI WILAYAH GEMPA TINGGI

2018 ◽  
Vol 7 (2) ◽  
pp. 57-64
Author(s):  
Alfian Wiranata Zebua
Keyword(s):  
Structural Analysis ◽  
Shear Force ◽  
Structure Model ◽  
Dynamic Shear ◽  
Earthquake Loads ◽  
Story Drift ◽  
Loads Analysis ◽  
Support Reactions ◽  
Static Shear

Abstract : Four stories building was used as structure model. Static earthquake loads distribution were determined according to SNI 1726:2012. The effect of dynamic earthquake loads also considered. The result of structural analysis determined using ETABS. It were static shear force 1.082,64 KN and dynamic shear force, Fx = 1.057 KN and Fy = 983,5 KN. Colomn and beam forces were also determined. Support reactions and joint displacements were determined through structural analysis. Mass modal participation has been reached over 90% at mode 5. Story drift was still smaller than the allowable story drift.Keywords : earthquake loads analysis, residential building.Abstrak:Model struktur yang dianalisis yaitu gedung beraturan lantai 4 untuk rumah tinggal. Distribusi beban gempa statik diperoleh sesuai dengan SNI 1726:2012. Pengaruh beban gempa dinamik juga diperhitungkan. Hasil analisis struktur diperoleh antara lain besaran gaya geser statik 1.082,64 KN dan gaya geser dinamik, Fx = 1.057 KN dan Fy = 983,5 KN. Besaran gaya elemen kolom dan balok juga diperoleh. Reaksi tumpuan serta perpindahan titik buhul dapat diketahui dari hasil analisis yang dilakukan. Pada mode 5, partisipasi massa model yang dianalisis sudah mencapai 90%.Simpangan antar lantai yang terjadi pada model struktur tidak melebihi simpangan yang diijinkan.Kata kunci : analisis gaya gempa, bangunan rumah tinggal.

scholarly journals Effect of Web Inclination on Box Girder Bridges

2020 ◽  
Vol 9 (12) ◽  
pp. 232-236
Keyword(s):  
Finite Element ◽  
Bridge Engineering ◽  
Easy Access ◽  
Finite Element Models ◽  
Box Girder Bridges ◽  
Box Girder ◽  
Class A ◽  
Girder Bridges ◽  
Live Loads ◽  
Support Reactions

Bridge is a key element in any transportation system which provides easy access over physical obstacles like road, valley, water bodies etc. without closing the way underneath. Among various types, use of box girder type bridges are gaining popularity in bridge engineering because of its better stability, serviceability, economy, aesthetics, structural efficiency and rigidity in torsion. In this study, a box girder is analyzed by changing its web inclination angle to the horizontal (90°, 83°, 76°, 69°, 62°) using finite element based software CSi Bridge. Finite element models are developed keeping material properties, span length, boundary conditions as constant parameters. All these models are analyzed for self-weight, including load of wearing coat and crash barrier, and live loads specified by Indian Road Congress (IRC) namely IRC Class 70R and IRC Class-A loading. Responses in terms of torsional moment, longitudinal moment, support reactions, displacement and stresses are determined.

scholarly journals Effects of Multi-Point Contacts during Object Contour Scanning Using a Biologically-Inspired Tactile Sensor

Sensors ◽  
2020 ◽  
Vol 20 (7) ◽  
pp. 2077 ◽  
Author(s):  
Lukas Merker ◽  
Sebastian J. Fischer Calderon ◽  
Moritz Scharff ◽  
Jorge H. Alencastre Miranda ◽  
Carsten Behn
Keyword(s):  
Steel Wire ◽  
Sense Organ ◽  
Tactile Sensor ◽  
Spring Steel ◽  
Point Contacts ◽  
Contact Points ◽  
Discrete Contact ◽  
Almost All ◽  
Rats And Mice ◽  
Support Reactions

Vibrissae are an important tactile sense organ of many mammals, in particular rodents like rats and mice. For instance, these animals use them in order to detect different object features, e.g., object-distances and -shapes. In engineering, vibrissae have long been established as a natural paragon for developing tactile sensors. So far, having object shape scanning and reconstruction in mind, almost all mechanical vibrissa models are restricted to contact scenarios with a single discrete contact force. Here, we deal with the effect of multi-point contacts in a specific scanning scenario, where an artificial vibrissa is swept along partly concave object contours. The vibrissa is modeled as a cylindrical, one-sided clamped Euler-Bernoulli bending rod undergoing large deflections. The elasticae and the support reactions during scanning are theoretically calculated and measured in experiments, using a spring steel wire, attached to a force/torque-sensor. The experiments validate the simulation results and show that the assumption of a quasi-static scanning displacement is a satisfying approach. Beyond single- and two-point contacts, a distinction is made between tip and tangential contacts. It is shown that, in theory, these contact phases can be identified solely based on the support reactions, what is new in literature. In this way, multipoint contacts are reliably detected and filtered in order to discard incorrectly reconstructed contact points.

Support Reactions

2009 ◽  
pp. 115-148
Author(s):  
Dietmar Gross ◽  
Werner Hauger ◽  
Jörg Schröder ◽  
Wolfgang A. Wall ◽  
Nimal Rajapakse
Keyword(s):  
Support Reactions
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